Electron discharge device



6, 1945. v. RONCI ELECTRON DISCHARGE DEVICE Nov.

Filed Aug. 8, 1941 3;: low \m...

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IN VE N 7' 0/? w L. RONC/ FIG.

A 7 TORNEY Patented Nov. 6, 1945 UNITED STATES EN CE.

ELECTRON DISCHARGE DEVICE;

Victor'L. Ronci, Brooklyn, N. Y-, assign'or'to Bell TelephoneLaboratories, Incorporated, New York, N. Y., a corporation of New YorkApplication August 8, 1941, Serial No. 405,938 7 Claims. (01. 250-275)This invention relates to electron discharge devices and moreparticularly to such devices operable at ultra-high frequencies andhaving cavity resonators associated with electrodes thereof.

In one class of electron discharge devices commonly designated asvelocity variation devices, the input or output systems or both includecavity resonators associated with gaps within an enclosing vessel anddefined by a pair of electrodes. The enclosing vessel is usually of avitreous material and parts at least thereof are within the highfrequency fields between the electrodes or gaps and the resonators sothat these parts absorb energy from the fields and thereby provide anenergy or power loss resulting in a decrease in the operating efiiciencyof the device. Also, the resonant frequency of such resonators isdependent upon the form and dimensions thereof so that when a change inthe operating frequency 1 is desired replacement of the resonator oftenis required or the introduction ofv some form of tuning means isnecessitated.

One object of this invention is, to reduce losses due to insulating orvitreous material within the high frequency fields of cavity resonators:asso-- ciated with ultra-high frequency electron dis charge devices andthereby to increase theoperating efilciencyof such devices. a

Another object of this invention is to'facilitate y the tuning of cavityresonators associated with electron discharge devices.

In one illustrative embodiment of this invention, an electron dischargedevice of the velocity variation type comprises an enclosing vessel having walls of vitreous or insulating material, an electron gun forproducing an electron beam, pairs of electrodes defining gaps traversedby the electron beam, and cavity resonators associated with the gapdefining electrodes and in energy transferring relation therewith.

In accordance with one feature of this invention, the cavity resonatorsconstitute wall portions; of the enclosing vessel, are conductivelyassociated with the gap defining electrodes, and together with the itelectrodes define a continuous electrical enclosure the interior ofwhich is sub stantially freeof vitreous or insulating material. Inaccordance with another feature ofthis invention, the cavity resonatorsare provided-with flexibleportions allowing alteration of the formoftheresonators and, hence, adjustment of the resonant irequencythereof.q l V 4 The invention and the above-notedand other features thereofwillJoe-understood more clearly and fully from the following detaileddescription with reference to the accompan ing drawing, in which:'

Fig. 1 is an elevational view partly in section of a velocity variationelectron discharge device illustrative of one embodiment of thisinvention;

Fig. 2 is an enlarged detail view in section showing the construction ofone of the cavity resonators included in the device illustrated in Fig.1 and showing also the association of the resonator with two gapdefining electrodes in the device; I y 7 Fig. 3 is a detail view sectionof a modification of the construction illustrated in Figs. 1 and 2particularly suitable forassociation with a coaxial transmission line;

Figs. 4A to 4F are detail sectional views of several cavity resonatorstructures made in accordance with this invention: and

Fig. 5 is a plan view of one of the grid electrodes and a portion of thecavity resonator associated therewith. I l

Referring now to the drawing, the electron discharge device shown Fig. 1comprises an enclosing vessel having three cylindrical vitreous portionsIlla, lllb and [0c andhous'i'ng an electron gunl I, which may be ofthecons'triiction disclosed in Patent 2,303,166 granted November 24,1942, to J oseph P. Laico, for projecting an electron beam axially ofthe enclosingve'sseL-a collector elec trode l2, and a cylindrical driftspace electrode I3. Mounted between the electron l1 and electrode l3 area pair of grid electrodes l4 and I5 defining an input gap [6 and havingassociated therewith a toroidal cavity resonator designated generally asIT. A second pair of grid electrodes 3 and I9 are mounted between thedrift space and collector electrodes, define an output gap 20 and haveassociated therewith a toroidal cavity resonator designated generally at2| similar in construction to the resonator l1.

During operation ofthe device, the electron stream produced by theelectron gun H crosses the gap 16 and, when the resonator I1 is energized, undergoes a velocityvariation. The stream then flows through thedrift space and is thus converted into a density varied beam whichtraverses the gap 20 and delivers energy to the resonator 2|. Energy maybe supplied to the resonator ll and taken from the resonator 2| in knownways.

As shown more clearly in Fig. 2, the cavity resonator 11 includes twosimilar, dished annular members each of which comprises an inne -annularportion 22d or 221) to which the grids I4 or I5 are secured and an outerannular portion 2317. or 23b. The portions 22 and 23 may be of copper orother metal copper coated or plated and corresponding portions may bebrazed or welded together. The outer portions 23 a and 23b may be weldedtogether adjacent their peripheries. The joints, whether welded, brazedor otherwise formed, are made in such manner that the parts joined aresealed hermetically to one another.

In the fabrication of the device, the annular portions 22a and 23a arejoined hermetically and the annuli 22b and 231) are similarly joined.The

which are illustrated in Figs. 4A to 4F, inclusive.

-In the construction illustrated in Fig. 4A, the

sufiiciently thin to allow tuning of the resonator annulus 22a is thenhermetically sealed to and-- between the vitreous cylinder la and aglass ring 24 and the annulus 22b is sealed. similarly to the.

vitreous cylinder [b and a glass "ring 25. The

grids I 4 and I are then secured suitably to the 1 respective annuli 22aand 22b and the outer annuli 23a and 23b are subsequently joinedadjacent their peripheries.

nuli 22a or 221) have substantially the same, coieflicients ofexpansion, the glass rings 24 orj25 may beomitted. 1 L j The grids l4and I5 may be composed of parallel wires and in the assembly of the:device or the manner described above, it will be appreciated that, ifdesired, the wires of the two grids may be aligned withrfacility.

The annular portions 23a and 232) are made of suflicient thickness toprevent contact between the two grids l4 and I5 and yet sufficientlythinso that they may be flexed by the application of pressure thereto toalter the form of the resonator and thereby tune it to a desiredfrequency. The flexing action is restricted to theportions 23a and 23bdue to the sealing of the portions 22a and 22b adjacent their.peripheries so that when the resonator is tuned the grids I}! and I5 aremaintained in parallel relation. g

It will be noted that the resonator and grids constitute an electricallycontinuous enclosure so that very close and eflicient coupling betweenthe electron stream'and the resonator is realized. The interior of thisenclosure is devoid.

of insulating materialexcept forthe glass rings 24 and 25, which are ofsmall volume, so that losses due to absorptioniof'energy from'the highfrequency fields are very smalland a correspond: ingly. high operatingefiiciency is, obtained. r H

The pressure for flexing the portions'23a and 23b may be applied throughany suitableinstrumentalities as, for example, through a pair of annularmembersfthreaded'to one another and each bearing against one of theannular portions 23a and 23b, or througha pair'of clamping membersengaging these annular portions and adjustably spaced by a suitablemicrometer drive. 7

.In the construction illustrated in Fig. 3, the cavity resonator 2! isprovided with a. plurality If the glass and metal employed for thecylinders Illa or [0b and the an- 7 by the application of pressurebetween the portions of these members outside of the cylinders,

as by application of pressure between the flanges .32. r

The construction illustrated in Fig. 4B is similar to that shown in Fig.4A except that the metallic members are of such form that the inof smallapertures through each of which a wire pick-up conductor 26 extends, theseveral conductorsv 23 being mounted on a flanged metallic support2lextending between and sealed hermetically to cylindrical'vitreousportions I 00 and llld of the enclosing vessel. Coaxial conductors 28and 29 are connected to theresonator ZlQand support 21 as shown andcouplethe resonator and pick-up conductors to a suitable load orcircuit. A similar coaxial line may be associated in the same mannerwith the resonator l1 associated with the input gap l6. The cavityresonators l1 and 2l may.bejo f a variety of forms. andconstructiona.Qther than those'shown in Figs. 1, 2 and 3,'a ;nurnber oftermediate portion of the resonator is rectangularin radial section. I

In the construction shown-in Fig. 40, the metallic members forming thecavity resonator are provided with flexible corrugated portions 33 whichfacilitate tuning of the resonator by flexure of wall portions thereof.

In the construction shown in Fig. 4D, the intermediate portion of theresonator is substantially entirely outside of the vitreous cylindersI00, and lilb and the inner flanges 3| are her- Although a number ofspecific embodimentsof this invention have been shown and described, itwill be understood that they are but illustrative and that variousmodifications may be made therein without departing from thesco'pe andspirit of this'invention' as defined in theapp'end'edclaims ""IIHV j i'Whatis claimedis': f I T f- J i .1. An electron discharge "device compris'ing means for producing an 'ele'ctron'stream, an electrode, a pair ofelectrodemembers'between 'said means and said electrode defininga'gapjmeans defining a cavity resonator including a pairfof annularmetallic members in juxtaposition and hermetically joined at theirperipneries; each of said annular members having an inner substantiallyrigid portion mounting one of saidelectrode members and having alsoanlouter' flexible portion, and an enclosing yesse 'ho smgsaiq nrstmeans, electrode members and electrodeand constituted in part by spacedparts of thefle'xible portions of said annular metalli members? c 2.Anelectron discharge'device comprising 'an enclosing vessel includin'g'apair oiifvitreouscylindrical members in spaced end-'to-endrel-ationjapair of juxtaposed annular metallic members defining a cavity resonatorandhavingjparts constitutingf a portion" 6f th enclosirig vessel, saidmetallic members bein'g"joinedfhrmetically at their peripheries andhermetically sealed to ljuxtaposed ends or" said cylindricalffnembergthespace bounded by said resonatonbing substantially free of insulatingintrane -spam l taposed electrodesjwithin saidvessel, defining agap n ad r s a r eea hsarn ri ib i said annular members, an electron gun withinsaid vessel and opposite one of said electrodes, and a collectorelectrode opposite the other of said members.

3. An electron discharge device in accordance with claim 2 wherein saidannular metallic members include juxtaposed wall portions outside ofsaid cylindrical members, deformable by pressure to tune the cavityresonator.

4. An electron discharge device comprising means defining a metallictoroidal cavity resonator the space within which is substantially freeof insulating material, said means including a pair of juxtaposedannular metallic members each having inner and outer flanges andintermediate dished portions, the outer flanges of said members beingjoined hermetically, an electrode mounted on the inner flange of one ofsaid members, a second electrode mounted on the inner flangeof the otherof said metallic members, an electron gun opposite one of saidelectrodes, a collector electrode opposite the other of said electrodes,and an enclosing vessel including a pair of aligned, cylindrical,insulating wall portions each joined hermetically to one of said annularmetallic members.

5. An electron discharge device comprising a pair of annular metallicmembers defining a cavity resonator and having inner portions andflexible outer portions, the outer portions being joined hermeticallyadjacent their peripheries, a pair of electrodes secured to the innerportions of said metallic members, an enclosing vessel constituted inpart by portions of said metallic members and having aligned cylindricalvitreous portions hermetically sealed to the inner portions of saidmetallic members, and a pair of electrodes within said vessel and incooperative relation with said first electrodes. I

6. An electron discharge devicecomprising an enclosing vessel includinga pair of vitreous cylindrical members in spaced end-to-end relation,means defining a toroidal cavity resonator, said means including a pairof inner annular metallic members hermetically sealed to the juxtaposedends of said cyindrical members and including also a pair of outerannular metallic members hermetically joined at their outer edges andeach joined hermetically to a corresponding one of said inner metallicmembers, a pair of substantially parallel electrodes within said vesseland each secured to a corresponding one of said inner annular members,and electrode means within said vessel in cooperative relation with saidelectrodes. p

7. An electron discharge device comprising an enclosing vessel includinga pair of vitreous cylindrical members in spaced end-to-end relation,means defining a toroidal cavity resonator including a pair of annularmetallic members between. and hermetically sealed to the juxtaposed endsof said vitreous members, said metallic members being joinedhermetically adjacent their peripheries, a pair of electrodes mounted bysaid metallic members, within said vessel and defining a gap, means forprojecting an electron stream across said gap, a plurality of pick-upconductors within said vessel and extending within said resonator, ametallic support mounting said conductors, hermetically sealed to andprojecting from said enclosing vessel, and coaxial conductors externalto said vessel connected one to said support and the other to saidresonator.

VICTOR L. RONCI.

